Nordic W/WH-Series Dual Circuit Owner's manual

Maritime Geothermal Ltd.

P.O. Box 2555, 170 Plantation Road

Petitcodiac, NB E4Z 6H4

(506) 756-8135

Commercial W-Series & WH-Series

Water to Water Heat Pumps

Dual Refrigeration Circuit

Model Sizes 150-1000 (12 to 81 ton)

info@nordicghp.com

www.nordicghp.com

002097MAN-04

ISSUE 03: 18-Oct-2023

Application, Installation, & Service Manual

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W - 400 - H - P - 2D - PP - xx

Series:

W = liquid to water

WH = high temperature liquid to water

(sizes 150-800 only)

Nominal Size:

150 = 12 ton

185 = 15 ton

240 = 20 ton

300 = 23 ton

400 = 30 ton

500 = 40 ton

600 = 50 ton

800 = 65 ton

900 = 70 ton

1000 = 81 ton

Functions:

H = Heating

AC = reversing valve (sizes 150-800 only)

W = desuperheater for DHW (sizes 150-400 only)

Refrigerant:

P = R410a (W series)

B = R134a (WH series)

Voltage Code:

1 = 208/230-1-60

2 = 208-3-60

4 = 460-3-60

5 = 575-3-60

6 = 220-1-50

7 = 380-3-50

8 = 400-3-60

Indoor Loop Exchanger:

P = brazed plate

Revision:

01, 02 etc.

Compressor:

D = dual scroll

Outdoor Loop Exchanger:

P = brazed plate

WARNING: Ensure all access panels are in place and properly secured before applying power to the unit.

Failure to do so may cause electrical shock.

WARNING: Before performing service or maintenance on the heat pump system, ensure all power sources

are DISCONNECTED. Electrical shock can cause serious personal injury or death.

WARNING: Heat pump systems contain refrigerant under high pressure and as such can be hazardous to

work on. Only qualified service personnel should install, repair, or service the heat pump.

CAUTION: Safety glasses and work gloves should be worn at all times whenever a heat pump is serviced.

A fire extinguisher and proper ventilation should be present whenever brazing is performed.

CAUTION: Venting refrigerant to atmosphere is illegal. A proper refrigerant recovery system must be

employed whenever repairs require removal of refrigerant from the heat pump.

SAFETY PRECAUTIONS

Model Nomenclature

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APPLICATION TABLE - W-SERIES

MODEL FUNCTION REFRIGERANT VOLTAGE COMPR. OUTDOOR COIL INDOOR COIL REVISIONS

W-150 H

HAC P

1

2

4

5

6

7

D P P 05

W-185

H P 2

4

5

7

D P P 03

HAC P D P P 04

W-240

H P 2

4

5

7

D P P 02

HAC P D P P 03

W-300

H P 2

4

5

7

D P P 02

HAC P D P P 03

W-400

H P 2

4

5

7

D P P 02

HAC P D P P 03

W-500

H P 4

5

7

D P P 02

HAC P D P P 03

W-600

H P 4

5

7

D P P 02

HAC P D P P 03

W-800

H P 4

5

7

D P P 02

HAC P D P P 03

W-900 H P

4

5

7

D P P 02

W-1000 H P

4

5

7

D P P 02

Maritime Geothermal Ltd. has a continuous improvement policy and reserves the right to modify specification data at any

time without prior notice .

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Maritime Geothermal Ltd. has a continuous improvement policy and reserves the right to modify specification data at any

time without prior notice .

APPLICATION TABLE - FIRMWARE AND PC APP

Firmware Version Associated PC APP Version

MGT GEN2 Bootload Firmware V3.60+ MGT GEN2 PC APP V2.00+

APPLICATION TABLE - WH-SERIES

MODEL FUNCTION REFRIGERANT VOLTAGE COMPR. OUTDOOR COIL INDOOR COIL REVISIONS

WH-150 H

HAC B

1

2

4

5

6

7

D P P 05

WH-185

H B 2

4

5

7

D P P 02

HAC B D P P 03

WH-240

H B 2

4

5

7

D P P 02

HAC B D P P 03

WH-300

H B 2

4

5

7

D P P 02

HAC B D P P 03

WH-400

H B 2

4

5

7

D P P 02

HAC B D P P 03

WH-500

H B 4

5

7

D P P 02

HAC B D P P 03

WH-600

H B 4

5

7

D P P 02

HAC B D P P 03

WH-800

H B 4

5

7

D P P 02

HAC B D P P 03

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Tables & Documents 6 
 
System Description  7 
General Overview  7 
1. Heating Mode  7 
2. Cooling Mode  7 
 
Installation Basics  8 
Unpacking the unit  8 
Unit Placement  8 
General Bill of Materials  8 
 
Wiring  9 
Power Supply Connections  9 
Indoor Loop Circulator Pump Wiring  9 
Outdoor Loop Circulator Pump Wiring  9 
Outdoor Loop Water Valve Wiring  9 
Indoor Loop Water Valve Wiring  10 
Control Transformer  10 
BACnet Control Connections  10 
Setpoint Control Connections 10 
Setpoint Control: Aux. Connections 10 
Signals/Hardwired Control Connections  11 
Disable Switch (field installed) 11 
Other Connections 11 
002188CDG - Typ. GEN2 Indoor Circ. Connections  12 
002067CDG - Typ. Heating Only Zone Wiring (Setpoint) 13 
002069CDG - Typ. Heating Only Zone Wiring (Signals) 14 
 
Piping & Loop Information 15 
Water Loop Connections  15  
Headers for Multiple Units 15 
Ground Loop Systems  16 
Open Loop Systems (Water Quality Guidelines) 16 
Modulating Water Valve  16 
002366PDG - Recommended Buffer Tank Piping 17 
002367PDG - Auxiliary Boiler Piping 18 
002528PDG - Buffer Tank Piping - Multiple Units 19 
002240PDG - DHW with Single Wall Condenser 20 
002252PDG - Two Tank Piping with a Rev. Heat Pump 21 
002527PDG - 2 Tank Piping w/Multiple Rev. Heat Pumps 22 
002288PDG - Two Tank Simultaneous Heating/Cooling 23 
001680PDG - Two Tank Sim. Heating/Cooling (Diverting) 24 
002286PDG - Geothermal Snow Melt w/Reheating 25 
000530PDG - Typical Zone Types 26 
 
Operation  27 
1. BACnet Control  27 
2. Signals / Hardwired Control  27 
3. Setpoint Control  27 
Setpoint Control Method 1 - Indoor Loop (ICR), One Tank 27 
Typical Temperature Setpoints 28 
Summer Setback 28 
Outdoor Reset 29 
Setpoint Control Method 2 - Indoor Loop (ICR), 2 Tanks 30 
Setpoint Control Method 3 - External HTS/CTS, One Tank  31 
a) Heat Pump Mode 31 
b) Chiller Mode 32 
Setpoint Control Method 4 - External HTS/CTS, 2 Tanks  33 
 
PC Application (PC APP) 34 
PC Application Menus 34 
 
LCD Interface & Menus 47 
     
BACnet Interface 49 
Table of Contents 
Startup Procedure 53 
Pre-start Inspection 53 
Unit Startup 54 
Startup Record 55 
 
Routine Maintenance 56 
 
Troubleshooting Guide 57 
 
Repair Procedures 66 
Pumpdown Procedure 66 
General Repair Procedure 66 
Vacuuming & Charging Procedure 66 
Compressor Replacement Procedure 67 
Control Board Replacement Procedure 68 
LCD Interface (Display) Board Replacement Procedure 69 
 
Model Specific Information 70 
Flow Rates & Volumes 70 
Refrigerant Charge  70 
Shipping Information 70 
Operating Temperature Limits 71 
Loop Pressure Drop Data 72 
 
Standard Capacity Ratings - W-Series 74 
Performance Tables (Heating/Cooling): W-150 76 
Performance Tables (Heating/Cooling): W-185 77 
Performance Tables (Heating/Cooling): W-240 78 
Performance Tables (Heating/Cooling): W-300 79 
Performance Tables (Heating/Cooling): W-400 80 
Performance Tables (Heating/Cooling): W-500 81 
Performance Tables (Heating/Cooling): W-600 82 
Performance Tables (Heating/Cooling): W-800 83 
Performance Tables (Heating/Cooling): W-900 84 
Performance Tables (Heating/Cooling): W-1000 85 
 
Performance Tables (Ice Making/Arena Application) 86 
 
Performance Tables: WH-150 91 
Performance Tables: WH-185 92 
Performance Tables: WH-240 93 
Performance Tables: WH-300 94 
Performance Tables: WH-400 95 
Performance Tables: WH-500 96 
Performance Tables: WH-600 97 
Performance Tables: WH-800 98 
 
Electrical Specifications - W Series 99 
Electrical Specifications - WH Series 100 
Electrical Diagrams (All Voltages) 101 
Refrigeration Circuit Diagrams 106 
 
Dimensions - Without Enclosure (Sizes 150-400) 109 
Dimensions - With Enclosure (Sizes 150-400) 110 
Dimensions - Without Enclosure (Sizes 500-1000) 111 
Dimensions - With Enclosure (Sizes 500-1000) 112 
 
Appendix A: Control Board Description 113 
 
Appendix B: USB Driver Installation 117 
 
Appendix C: PC App Installation (Win11) 118 
 
Appendix D: PC App Installation (Win10) 119 
 
Appendix E: Updating Firmware  120 
 
Warranty 123 

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Tables & Documents 
Table 1 - Power Supply Connections .............................................................................................................. 9 
Table 2 - Indoor & Outdoor Circulator Connections ......................................................................................... 9 
Table 3 - Water Valve Connections ............................................................................................................... 10 
Table 4 - BACnet Connections ...................................................................................................................... 10 
Table 5 - Setpoint Control Connections ......................................................................................................... 10 
Table 6 - Setpoint Control: Aux. Connections ................................................................................................ 11 
Table 7 - Signals Control Connections .......................................................................................................... 11 
Table 8a - Typical W-Series Aquastat Settings ............................................................................................. 11 
Table 8b - Typical WH-Series Aquastat Settings ........................................................................................... 11 
Table 9 - Loop Connection Sizes................................................................................................................... 15 
Table 10 - Horizontal Headers Size for Multiple Units ................................................................................... 15 
Table 11 - Buffer Tank Size ........................................................................................................................... 15 
Table 12 - Water Quality Limits ..................................................................................................................... 16 
Table 13a - Typical W-Series Setpoints ........................................................................................................ 28 
Table 13b - Typical WH-Series Setpoints ...................................................................................................... 28 
Table 14 - Typical Setpoints: HTS/CTS Method, Chiller Mode ...................................................................... 32 
 
Table 15 - BACnet Objects - Control Signals (Read/Write) ........................................................................... 49 
Table 16 - BACnet Objects - Operation Mode Description (Read Only) ........................................................ 49 
Table 17 - BACnet Objects - Limits Description (Read Only) ........................................................................ 49 
Table 18 - BACnet Objects - Data (Read Only) ............................................................................................. 50 
Table 19 - BACnet Objects - Alarm Descriptions (Read Only) ...................................................................... 51 
Table 20 - BACnet Objects - Fault Descriptions (Read Only) ........................................................................ 52 
 
Table 21 - Flow Rates & Volumes ................................................................................................................. 70 
Table 22 - Refrigerant Charge (Per Circuit) ................................................................................................... 70 
Table 23 - Shipping Information .................................................................................................................... 70 
Table 24a - W-Series Operating Temperature Limits .................................................................................... 71 
Table 24b - WH-Series Operating Temperature Limits .................................................................................. 71 
Table 25 - Loop Pressure Drop Data ............................................................................................................. 72 
Table 26 - W-Series Standard Capacity Ratings ........................................................................................... 74 
Table 27 - W-Series Electrical Specifications ................................................................................................ 99 
Table 28 - WH-Series Electrical Specifications ........................................................................................... 100 
 
Table A1 - Control Board Connector Descriptions (Top)  ............................................................................ 114 
Table A2 - Control Board Connector Descriptions (Left Side)  .................................................................... 114 
Table A3 - Control Board Connector Descriptions (Bottom)  ....................................................................... 115 
Table A4 - Control Board Connector Descriptions (Right Side)  .................................................................. 116 
 
002188CDG – Commercial W Typical ICR Connections for GEN2 Setpoint Control .................................... 12 
002067CDG - Typical Zone and Auxiliary Wiring with GEN2 Setpoint Control (Heating Only) ...................... 13 
002069CDG - Typical Zone and Auxiliary Wiring with GEN2 Hardwired Option (Heating Only) ................... 14 
002366PDG - Recommended Hydronic Buffer Tank Piping  ......................................................................... 17 
002367PDG - Auxiliary Boiler Piping  ............................................................................................................ 18 
002528PDG - Buffer Tank Piping - Multiple Units ......................................................................................... 19 
002240PDG - High Temperature Single Wall Unit Connection to DHW Tank ............................................... 20 
002252PDG - Two Tank System Piping with a Reversing Heat Pump  ......................................................... 21 
002527PDG - Two Tank Piping with Multiple Reversing Heat Pumps ........................................................... 22 
002288PDG - Two Tank Simultaneous Heating / Cooling  ............................................................................ 23 
001680PDG - Two Tank Simultaneous Heating / Cooling (Diverting Arrangement) ...................................... 24 
002286PDG - Geothermal Snow Melt System with Warm-Weather Ground Loop Reheating  ...................... 25 
000530PDG - Typical Zone Types for Hydronic Applications ........................................................................ 26 
 
001717SCH - W-150 to 1000-H***-*-*D-PP High Voltage Schematic Diagram ........................................... 101 
002414SCH - W-150 to 1000-H***-*-*D-PP w/Disconnect High Voltage Schematic Diagram ..................... 102 
001718SCH - W-150 to 1000-H***-*-*D-PP Schematic Diagram................................................................. 103 
001719ELB - W-150 to 1000-H***-*-*D-PP Electrical Box Diagram ............................................................ 104 
002415ELB - W-150 to 1000-H***-*-*D-PP w/Disconnect Electrical Box Diagram ...................................... 105 
001720RCD - W-150 to W-1000-H(W) Refrigeration Circuit Diagram - Heating Mode................................ 106 
001721RCD - W-Series HAC(W) (150-800) Dual Circuit Refrigeration Circuit Diagram—Heating Mode .... 107 
001722RCD - W-Series HAC(W) (150-800) Dual Circuit Refrigeration Circuit Diagram—Cooling Mode .... 108 
Tables 
 
Documents

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System Description

General Overview

These units are 2-compressor dual refrigeration circuit

water-to-water heat pumps. They have a ‘vertical chiller’ style

design with external loop headers, for ease of passage through

doors and convenience for multiple-unit installations. They are

available in any world electrical service.

The W-series uses R410a refrigerant to achieve a stand-

ard geothermal temperature range: the outdoor loop can oper-

ate at as low a temperature as 0°F (-17°C) for ice production,

and the indoor loop can reach 130°F (54°C) leaving water tem-

perature under standard ground loop conditions.

The WH-series uses R134a refrigerant to achieve an

upward shift in temperature range: the outdoor loop requires a

minimum incoming water temperature of 45°F (7°C), so is suita-

ble for use on many open loop or heat recovery applications, or

closed ground loops in warm climates. The indoor loop can

reach 160°F (71°C) leaving water temperature.

The units are built on industrial-strength steel frames, with

removable enclosure insulated with 1” insulation. The indoor

and outdoor loop hydronic heat exchangers are both true dual

circuit stainless steel brazed plates with copper brazing. Two

single-stage scroll compressors are standard, as are two Elec-

tronic Expansion Valves (EEV’s). The electronic control board

has full local unit hydronic temperature control, laptop connec-

tivity via USB with free PC App, LCD interface, electronic

readout of all pressures and temperatures, data logging & gra-

phing, and BACnet.

1. Heating Mode

In heating mode, the heat pump heats water in an indoor

loop or buffer tank, while extracting heat from an outdoor loop.

For commercial environments, heat pumps are normally

sized and the system laid out by a mechanical consulting engi-

neer. It is good practice to design the system with non-

reversing heat pumps that always use ‘heating mode’: heating

with the hot indoor loop, and cooling with the chilled outdoor

loop. (See simultaneous heating-cooling diagrams in the Pip-

ing chapter.) Multiple units are easily installed side by side with

zero clearance using horizontal headers, to provide redundancy

as well as the ability to meet large loads. Control is normally

done using the building control system via BACnet, and includes

lead/lag stage rotation to evenly distribute the run hours be-

tween compressors. Loop circulation pumps are also centrally

controlled via BACnet.

It is also possible to use the heat pump in standalone op-

eration or in small numbers of units. In this case, hydronic tem-

perature control functionality built into the heat pump may be

used, and circulation pumps and/or water valves (either on/off or

modulating) can be powered and controlled by the heat pump.

A third control option is through dry contacts by an external ther-

mostat or controller.

Hydronic heating systems are easily zoned, and zones

may be in-floor heating, hydronic air handlers, or other hydronic

devices suitable for the water temperature. When a zone re-

quires heat, its zone thermostat calls for a zone circulator pump

or zone valve to activate, so that hot water from the buffer tank

is sent to the zone requiring heat. Note that there is no direct

connection between the zone thermostat and the heat pump,

the functions of each being separated by the buffer tank.

2. Cooling Mode (HAC models only)

Reversing valves to swap the hot and cold loops are avail-

able on model sizes up to 400 (see Application Table on page

3). When reversing valve is activated, the indoor loop or buffer

tank is chilled, and heat is rejected to the outdoor loop.

Hydronic cooling is usually done through hydronic air han-

dlers, which have condensate drains to remove water that is

removed while dehumidifying the air. In less humid climates, in-

floor or radiant cooling is sometimes performed; such systems

can’t remove humidity from the air. In this case, care must be

taken to ensure the cooling surface does not fall below the dew

point temperature in order to prevent condensation on floor sur-

faces.

Four W-1000 heat

pumps with enclosures

installed, and 8”

external horizontal loop

headers

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Installation Basics

Unpacking the Unit

When the heat pumps reach the site, they should be

unpacked to determine if any damage has occurred during

shipment. Any visible damage should be noted on the carrier's

freight bill and a claim filed.

Unit Placement

Locate the unit as per the system design drawings. The

access panels on the ends of the units should remain clear of

obstruction for a distance of 3 ft (1 m) to facilitate installation

and servicing.

Note that for multiple unit installations, horizontal headers

will connect the units on the piping end. Extra space must be

allotted for the headers, which can be of substantial size

(up to 12” in diameter). Space for external accessories must

also be planned for, e.g. strainers and valves (manual, electron-

ic, balancing, or modulating). Headers and accessories are not

included with the heat pump, and must be ordered or sourced

separately.

Since all serving can be done from the ends, no access is

required to the long side panels, which are fully removable

from the ends. This means that multiple units can be installed

side by side with minimal clearance, although if large headers

obstruct access to the piping-end panels, side clearance may be

provided to ease access to the components located there.

The heat pumps are provided with rubber mounting feet

(shipped inside electrical box), which must be installed on site.

These will preserve the frame finish and dampen vibrations

when used on solid concrete floors. Optional spring feet should

be ordered when heat pump is installed on floors with flex, e.g.

mezzanines.

General Bill of Materials

This is not an exhaustive list, but is an example of the ma-

terials that may be required for a commercial installation.

FROM MARITIME GEOTHERMAL

• W/WH SERIES HEAT PUMP(S)

• INSULATED ENCLOSURE(S) [STANDARD]

OPTIONAL FROM MARITIME GEOTHERMAL

• SPRING FEET FOR MEZZANINE INSTALLATION

• OUTDOOR TEMPERATURE SENSOR FOR OUTDOOR

RESET WHEN USING ONBOARD SETPOINT CONTROL

• HOT/COLD TANK TEMPERATURE SENSORS

• 0-10V MODULATING WATER VALVE(S)

LOOPS (AS SPECIFIED BY SYSTEM DESIGNER)

• FABRICATED HORIZONTAL HEADERS

• GROOVED (VICTAULIC) FLEXIBLE COUPLINGS

• STRAINERS - 16 MESH / 1 MM

• ON/OFF WATER VALVES

• BUTTERFLY (HAND) VALVES

• BALANCING VALVES

• CIRC. PUMPS, SIZED FOR REQUIRED FLOW & dP

• PIPE & FITTINGS

• ANTIFREEZE: METHANOL OR PROP. GLYCOL

• BUFFER TANK, OPT. W/ELEMENTS __kW

• SECONDARY WATER TO WATER HEAT EXCHANGERS

ZONES

• ZONES CIRCULATOR(S)

• ZONE TRANSFORMER & CIRC CONTACTOR

• ZONE VALVES (IF NOT INDIVIDUAL PUMPS)

• IN-FLOOR PIPING

• OTHER AIR HANDLERS, DUCTING

• ZONE THERMOSTATS

• RELAYS OR ZONE CONTR. (REVERSING SYSTEMS)

• ZONE SUPPLY & RETURN HEADERS

• PIPE & FITTINGS TO ZONES

• EXPANSION TANK

ELECTRICAL

• HEAT PUMP SERVICE WIRE

• BUFFER TANK ELEMENT SERVICE WIRE

• HEAT PUMP BREAKER

• BUFFER TANK ELEMENT BREAKER

• CONTACTOR & ELEC. BOX (IF NOT WITH TANK)

• THERMOSTAT WIRE 18-4

• THERMOSTAT WIRE 18-2

• FORK TERMINALS FOR TSTAT WIRE (6)

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Wiring

Power Supply Connections

The heat pump electrical box and also the enclosure (if

used) have several knockouts of various sizes for the electrical

connections.

A schematic diagram (SCH) and electrical box layout

diagram (ELB) can be found on the electrical box cover of the

unit as well as in the Model Specific Information chapter of

this manual.

The Electrical Specifications in the Model Specific Infor-

mation chapter contain information about the size of wire for the

connections, as well as the recommended breaker size. These

should be checked by referencing MCA and FLA by a qualified

professional to ensure conformance to local codes. Power sup-

ply connections to the unit are made directly to the power block

inside the electrical box and are as per TABLE 1. Ground is to

be connected to the GND lug inside the electrical box.

IMPORTANT NOTE: A properly qualified

electrician should be retained for all

connections to the heat pump and associat-

ed controls. The connections to the heat

pump MUST CONFORM TO LOCAL CODES.

Outdoor Loop Circulator Pump Wiring

The outdoor loop circulator provides flow between the heat

pump and the outdoor loop. In most multiple-unit commercial

installations, the circulators (and the heat pump) will be con-

trolled by the building automation system, since one circulator

may serve several heat pumps. Connect circulator pumps as

per site drawings.

If the heat pump is to control the outdoor circulator, there

are dry contacts provided to control the circulator pump so that it

will be turned on whenever the compressor operates. Wire to

CP1 and CP2 on the terminal strip at the lower right side of elec-

trical box, as shown on the following diagram 002188CDG and

the wiring diagram (SCH) in the Model Specific Information

chapter of this manual. Ensure that the total current draw does

not exceed the value indicated on the diagram.

There is also provision for directly connecting an outdoor

circulator contactor with 24VAC coil, without external 24VAC

transformer. See “Outdoor Water Valve Wiring - ON/OFF”, be-

low.

IMPORTANT: If the outdoor circulator is connected via CP1 and

CP2, it may be unnecessarily activated at times when the com-

pressor is not running, if using the Setpoint Control option

(refer to Setpoint Control chapter of this manual). Under Set-

point Control, the heat pump will start and stop indoor circulators

connected via CP1 and CP2 to sample the water temperature

when the heat pump is not operating. Therefore, if using Set-

point Control, outdoor circulators should be connected as per

“Outdoor Water Valve Wiring - ON/OFF”, below.

TABLE 2 - Indoor & Outdoor Circulator Connections

Terminal Description

CP1 Dry contacts for circulator control

CP2

Use a 2-conductor 18ga cable.

TABLE 1 - Power Supply Connections

Line Description Voltages

L1 Line 1 All

L2 Line 2 All

L3 Line 3 All 3-phase (208-3-60, 460-3-60,

575-3-60, 380-3-50)

N Neutral No Connection

Indoor Loop Circulator Pump Wiring

The indoor loop circulator provides flow between the heat

pump and the buffer tank. In most multiple-unit commercial

installations, the circulators (and the heat pump) will be con-

trolled by the building automation system, since one circulator

may serve several heat pumps. Connect circulator pumps as

per site drawings.

If the heat pump is to control the indoor circulator, there

are dry contacts provided to control the circulator pump so that it

will be turned on whenever the compressor operates. Wire to

CP1 and CP2 on the terminal strip at the lower right side of

electrical box, as shown on the following diagram 002188CDG

and the wiring diagram (SCH) in the Model Specific Infor-

mation chapter of this manual. Ensure that the total current

draw does not exceed the value indicated on the diagram.

There is also provision for directly connecting an indoor

circulator contactor with 24VAC coil, without an external 24VAC

source. See “Indoor Water Valve Wiring - ON/OFF”, below.

The indoor circulator only will be activated at times when

the compressor is not running, when using Setpoint Control

(refer to Operation chapter of the manual). The heat pump will

start and stop indoor circulators to sample the water tempera-

ture.

Outdoor Loop Water Valve Wiring

ON/OFF: Connect a 24VAC outdoor loop water valve between

OV1 and GND (terminals DO_0 and LC on control board), as

shown on the wiring diagram (SCH) in the Model Specific In-

formation chapter. Ensure that the total current draw of all wa-

ter valves does not exceed the value indicated on the diagram.

The outdoor circulator contactor may be connected in the

same way, to avoid need for an external 24VAC transformer or

to avoid activation during sampling when using Setpoint Control.

MODULATING: Connect a 0-10VDC or PWM water valve be-

tween OV2 and GND (terminals PWM3 and GND on control

board), as shown on the wiring diagram (SCH) in the Model

Specific Information chapter. An outdoor modulating water

valve will give the control board the means to restrict the out-

door loop water flow in cooling mode on reversing units, in case

a low outdoor loop temperature causes a dip in the head pres-

sure and therefore suction pressure. This will prevent nuisance

low pressure control trips, for example when using cold open

loop well water in cooling mode. It will be closed when unit is

off, and may act to limit suction pressure due to high outdoor

loop temperature in heating mode depending on firmware revi-

sion.

The head pressure below which the modulating water

valve will start restricting water flow can be adjusted via the

Configuration page in the PC App. Default is 350 psi.

IMPORTANT NOTE FOR 3-PHASE UNITS: If

on startup compressor is noisy and not

pumping, reverse L1 and L2 supply wires.

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Control Transformer

The low voltage controls for 208/230-1-60 and 208-3-60

models are powered by a class II transformer with resettable

breaker on the secondary side for circuit protection. Should the

breaker trip, locate and correct the problem and then reset the

breaker by pressing in on it.

All other voltage models have a transformer with primary

and secondary fuses for circuit protection.

IMPORTANT NOTE: For 208/230VAC-1-60

units, if connecting to 208VAC power supply

move the red wire connected to the 240 ter-

minal of the transformer to the 208 terminal

of the transformer.

Setpoint Control Connections

If not using a building automation system for control, the

heat pump’s built in aquastat functionality (with optional outdoor

reset) known as “Setpoint Control” may be used. Refer to the

Operation chapter of this manual for more information. If this

control method is used, it eliminates the need for an external

aquastat, and the ICR option also eliminates temperature probe

in the tank(s). It provides a three stage system along with delay

timer for the hydronic auxiliary heat.

No external control signals are required for non-reversing

H models. For reversing HAC models, a dry contact between

RA and the O signal is required to switch to cooling mode.

Drawing 002067CDG shows a typical wiring setup for zones,

zone circulator and hydronic auxiliary.

Note that for reversing models in cooling mode, it is im-

portant to choose zone thermostats or other control devices that

continuously return an “O” signal, even when there is no cooling

demand. This is to avoid repeated heating and cooling of the

buffer tank on demand cycling, causing temperature lags and

high electricity consumption.

Setpoint Control does not currently incorporate any lead/

lag or other coordination between multiple units; that is, each

heat pump operates independently. A small number of units

connected to the same buffer tank may operate under Setpoint

Control by using different setpoint temperatures for each stage

of each heat pump.

TABLE 5 - Setpoint Control Connections

Signal Description

C or CA 24VAC common (ground)

R or RA 24VAC hot

O Reversing valve (HAC models only)

Use a 3-conductor 18ga cable.

An external temperature probe may be used with the on-

board Setpoint Control routine, or two probes (one for hot tank

and one for cold tank) may be used. This is HTS/CTS Setpoint

Control; see Piping and Operation chapters for details.

Setpoint Control: Aux. Connections

When using Setpoint Control, hydronic auxiliary heat is

activated with a 24VAC signal from DO_2 (HYD_AUX) on the

left side of control board.

BACnet Control Connections

In most multiple-unit commercial installations, the heat

pump will be controlled by the building automation system. If

using BACnet MS/TP for external control of heating/cooling de-

mand and/or monitoring of status, use a shielded twisted pair to

the connector at the bottom left of control board. There is an

optional termination jumper located above the connector.

See the BACnet Interface chapter for wiring tips and ob-

ject names.

TABLE 4 - BACnet Connections

Line Description

A Communication +

B Communication -

GND Ground

Use a shielded twisted pair cable.

Indoor Loop Water Valve Wiring

ON/OFF: Connect a 24VAC indoor loop water valve between

IV1 and GND (terminals DO_1 and LC on control board), as

shown on the wiring diagram (SCH) in the Model Specific In-

formation chapter. Ensure that the total current draw of all

water valves does not exceed the value indicated on the dia-

gram.

The indoor circulator contactor may be connected in the

same way, to avoid the need for external 24VAC transformer.

MODULATING: Connect a 0-10VDC or PWM water valve be-

tween IV2 and GND (terminals PWM4 and GND on control

board), as shown on the wiring diagram (SCH) in the Model

Specific Information chapter of this manual. An indoor modu-

lating water valve will give the control board the means to re-

strict the indoor loop water flow in heating mode, in case a low

indoor loop temperature causes a dip in the head pressure and

therefore suction pressure. This will prevent nuisance low pres-

sure control trips, for example in case a large zone containing

cool water opens, or in case of generally low indoor loop tem-

perature. It will be closed when unit is off (and not sampling for

Setpoint Control). On reversing HAC units in cooling mode,

valve may act to limit suction pressure due to high indoor loop

temperature depending on firmware revision.

The head pressure below which the modulating water valve

will start restricting water flow can be adjusted via the Configu-

TABLE 3 - Water Valve Connections

Control

Board

Label

Signal

Name Description

PWM4 IV2 0-10VDC control signal for indoor modu-

lating water valve

PWM3 OV2 0-10VDC control signal for outdoor mod-

ulating water valve

GND - Common/ground for IV2, OV2

DO_1 IV1 24VAC output to actuate indoor water

valve or circulation pump contactor coil

DO_0 OV1 24VAC output to actuate outdoor water

valve or circulation pump contactor coil

LC - Common/ground for IV1, OV1

Use 18ga cable.

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The following tables show typical settings for the aq-

uastats. With these settings, stage 1 will activate when the tank

temperature reaches the activation point. If the load is too great,

the tank temperature will continue to drop when heating until

stage 2 is activated. As the tank temperature stops dropping

and begins to increase when heating, stage 2 will turn off before

stage 1, rather than at the same time as stage 1. There are

three main advantages to this:

• Less aquastat probe lag leading to reduced overshoot as the

tank temperature rate of change is reduced when only stage

1 is active.

• Prolonged stage 1 runtime leads to increased efficiency.

• Reduced number of compressor starts.

The settings may be changed as desired; however stage 1

setpoint for heating should not exceed 130°F (54°C) for W-

series and 160°F (71°C) for WH-series; stage 1 cooling setpoint

should not be set below 43°F (6°C) for W-series and 45°F (7°C)

for WH-series. Exceeding these setpoint limits will cause the

heat pump operating pressures to approach the safety control

settings, possibly causing nuisance shutdowns.

If only floor zones are being heated, it is highly recom-

mended to drop each of the heating setpoints by 15°F (8°C)

for increased efficiency.

A buffer tank with electric elements can be used to provide

Signals/Hardwired Control Connections

Most installations will use BACnet or the Setpoint Con-

trol routine to control buffer tank temperature, in which case no

aquastat is required. However, an aquastat or aquastats can be

used if required, for example if heating two loops with different

setpoint temperatures, or using a time-of-day or other third-party

programmable controller. This is Signals or Hardwired Con-

trol.

The CA, RA, Y1A , Y2A, and O connections are located

on the right side towards the top of the control board, as shown

on the wiring diagram in the Model Specific Information chap-

ter. The external device needs to send the 24VAC signal from

RA back to the Y1A terminal to call for compressor 1, to the

Y2A terminal to call for compressor 2, and to O to select cooling

mode (reversing HAC models only). CA is the common or

TABLE 7 - Signals Control Connections

Signal Description

CA 24VAC common (ground)

RA 24VAC hot

O* Cooling mode (reversing valve both stages)*

Y1A Compressor #1 (bottom)

Y2A Compressor #2 (top)

* HAC models only

TABLE 6 - Setpoint Control: Aux. Connections

Signal Description

LC 24VAC common (ground)

DO_2 Hydronic Auxiliary (hot)

Use a 2-conductor 18ga cable.

Disable Switch (field installed)

A switch or dry contact to disable demand from the con-

trol system may be installed. On control board, jumper COM_IN

to GND, and toggle 12VDC to IN_SPARE to disable. See wiring

diagrams in the Model Specific Information chapter.

Other Connections

An accessory outdoor temperature sensor is available, to

enable Setpoint Control’s Outdoor Reset functionality.

Dry contacts to separately indicate stage 1 and stage 2

alarms are available, as is an “L” 24VAC trouble indicator signal.

See wiring diagram in the Model Specific Information

chapter for details.

This powers the coil of an external contactor to operate

hydronic auxiliary heat. This signal can provide a maximum

of 500mA at 24VAC. If using an auxiliary heating device with

its own controller and transformer that requires dry contacts to

activate, a relay with 24VAC coil must. be added.

TABLE 8a - Typical W-Series Aquastat Settings

HEATING

Stage 1

(aquastat)

Stage 2

(aquastat)

Stage 3

(tank controller)

°F °C °F °C °F °C

Setpoint 108 42 105 41 100 38

Delta 8 4 8 4 8 4

Activation * 100 38 97 37 92 34

Delay 10 minutes

COOLING Stage 1 Stage 2

*Activation is

determined by

the Setpoint and

Delta values

°F °C °F °C

Setpoint 45 7 48 9

Delta 8 4 8 4

Activation * 53 11 56 13

auxiliary heat. When using Hardwired Control, a mechanical

tank element thermostat can be set to maximum, allowing the

electric elements to be controlled by an external contactor

placed in the power supply connections; the contactor can be

connected to stage 2 of the heating aquastat via an optional 0-

2hour timer. Or if the tank has an electronic controller, it can be

set to run according to its own setpint, which should be set lower

than that of the heat pump. Diagram 002069CDG show a typi-

cal wiring setup for zones, zone circulator, and hydronic auxiliary

for a heating only system.

Note that for reversing models in cooling mode, it is im-

portant to choose zone thermostats or other control devices that

continuously send an “O” signal, even when there is no cooling

demand. This is to avoid repeated heating and cooling of the

buffer tank on demand cycling, causing temperature lags and

high electricity consumption.

TABLE 8b - Typical WH-Series Aquastat Settings

HEATING

Stage 1

(aquastat)

Stage 2

(aquastat)

Stage 3

(tank controller)

°F °C °F °C °F °C

Setpoint 150 66 147 64 130 54

Delta 8 4 8 4 20 10

Activation * 142 62 139 60 110 44

Delay 10 minutes

COOLING Stage 1 Stage 2

*Activation is

determined by

the Setpoint and

Delta values

°F °C °F °C

Setpoint 45 7 48 9

Delta 8 4 8 4

Activation * 53 11 56 13

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TABLE 11 - Buffer Tank Size

Heat Pump

Size

Minimum Size

gal (L)

Recommended Size

gal (L)

150 100 (380) 120 (450)

185 130 (500) 180 (680)

240 160 (600) 200 (750)

300 200 (750) 250 (950)

400 250 (950) 300 (1100)

500 320 (1200) 400 (1500)

600 400 (1500) 500 (1900)

800 520 (2000) 600 (2300)

900 560 (2100) 600 (2300)

1000 648 (2450) 800 (3000)

TABLE 9 - Loop Connection Sizes

Model Size Connection Size (SS grooved/Victaulic)

150

2” (51 mm)

185

240

300

400

500

3” (76 mm)

600

800

900

1000

Piping & Loop Information

Water Loop Connections

The Outdoor Loop (Supply) and Indoor Loop (Hot) con-

nections are stainless steel pipe designed for Victaulic connect-

ors. The connection sizes are shown in the following table.

Piping should be done as per the system piping diagram as well

as local codes. It is recommended that all piping be insulated to

prevent condensation. All piping connected to the unit must be

sufficiently externally supported so as not to strain the heat ex-

changer connections.

To avoid fouling of the brazed plate heat exchangers, a

strainer is required on each loop IN connection. The strainer

should be specified to stop particles larger than 1 mm, and cor-

responds to a mesh size of 16-20 depending on wire diameter.

For closed loops, the strainer may be able to be removed after

startup and commissioning is complete and a cleaned filter

shows no removed particles after 1 week of operation.

Each port has a temperature sensor. The output is shown

on the LCD Interface on the unit and may also be viewed via the

PC APP. There is also a P/T port installed in each line, for

measuring pressure drop for flow rate estimation. Both of the

“OUT” ports have a flow switch on reversing models; only on the

outdoor loop for non-reversing models.

Buffer tank sizing should be as per the engineering specifi-

cations for the jobsite. However, the minimum buffer tank

size should follow the rule of 8 US gallons per ton of heat

pump capacity to avoid problems with short-cycling the

heat pump(s). The table shows the minimum buffer tank size

for each heat pump along with the recommended size. The

recommended size will provide longer runtimes and fewer starts

for improved efficiency.

IMPORTANT NOTE: Units are shipped configured for water

for both the indoor and the outdoor loop. This prevents the

heat exchangers from freezing when a low pressure alarm

occurs regardless of the fluid type and mixture in the sys-

tem loops. During startup the fluid type and mixture for

both the indoor and outdoor loop must be configured via

the PC APP using the Tools - Configuration menu. (There is

no need for antifreeze with WH-series due to source tem-

perature limitation of 45°F / 7°C.)

WARNING: ENSURE FLUID TYPE SETTING ARE

ACCURATE. FAILURE TO DO SO COULD

CAUSE THE HEAT EXCHANGER TO FREEZE

AND RUPTURE, DESTROYING THE HEAT PUMP

AND VOIDING THE WARRANTY.

WARNING: REPEATED RESETS OF A LOW

PRESSURE LOCKOUT COULD CAUSE THE

HEAT EXCHANGER TO FREEZE AND RUP-

TURE, DESTROYING THE HEAT PUMP AND

VOIDING THE WARRANTY.

TABLE 10 - Horizontal Header Size for Multiple Units

Number of

Heat Pumps

Heat Pump Con-

nection Size

Min. Nominal SCH40

Pipe Size for Header

2 2” (51 mm) 3”

3” (76 mm) 5”

3 2” (51 mm) 4”

3” (76 mm) 6”

4 2” (51 mm) 5”

3” (76 mm) 8”

5 2” (51 mm) 5”

3” (76 mm) 8”

6 2” (51 mm) 6”

3” (76 mm) 8”

7 2” (51 mm) 6”

3” (76 mm) 10”

2” (51 mm) 6”

8 3” (76 mm) 10”

Headers for Multiple Units

Horizontal headers with equally spaced side connections

for multiple units may be fabricated by the mechanical contrac-

tor (the usual practice), or ordered with the heat pumps. In ei-

ther case, detailed plans and a list of required accessories

(strainers, valves) must be provided.

The header pipe must have at least the capacity of all the

heat pump connections combined. See the following table for

minimum header sizes.

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Modulating Water Valve

A 0-10VDC modulating motorized water valve controlled

by the Gen2 control board in the heat pump may be required on

the indoor or outdoor loops depending on transient or steady

state loop operating temperatures. See Wiring chapter, and the

Operating Temperature Limits table in the Model Specific

Information chapter.

The modulating water valve is available as an accessory

from Maritime Geothermal Ltd., and can be installed on either

the loop’s IN or OUT connections at the heat pump. Depending

on size, valve connections may be threaded or flanged, and

two grooved (Victaulic) adapters should be used per valve.

Note that where installed, the modulating water valve will

act as the water shutoff valve, and no additional solenoid valve

is required.

CAUTION: if a modulating water valve is not

installed where its use is indicated, nuisance

low pressure control trips may occur.

Ground Loop Systems

Note that in northern climates, only the W-series is suita-

ble for use with a closed ground loop (WH is generally not suita-

ble due to its minimum required source temperature of 45°F/7°

C).

Commercial ground loop design is beyond the scope of

this manual, and is normally performed by mechanical consult-

ing engineering firms. For concept stage planning, it may be

considered that approximately one vertical loop of 150 ft depth

per nominal ton of heat pump capacity will be required; or there

can be a smaller number of deeper wells. Note that a different

borehole length per ton may be required if ground conductivity

or load balance vary from the average, and that due to the cost

of a commercial installation, a test well to measure ground con-

ductivity is often drilled before ground loop design is finalized.

Loops must be placed far enough apart to avoid excessive ther-

mal interference, e.g. 20 ft / 6 m apart. Loops are normally

headered together underground, with care taken to size the

headers properly so that purging of air is possible with reasona-

bly sized pumping equipment.

Note that adequate freeze protection for the loop fluid is

required. The proper type and quantity of antifreeze must be

added to the ground loop as per the system design.

WARNING: It is recommended that enough

antifreeze be added to allow for a temperature

20°F (11°C) lower than the expected lowest

loop fluid temperature entering the heat pump.

It is important to size ground loop circulation pumps to

deliver the required flow as listed in the table in the Model Spe-

cific Information chapter, considering the expected pressure

drop of the antifreeze mixture used through the heat pumps and

ground loop and all accessories. Low flow rate due to under-

sized circulation pumps causing low heat pump performance or

safety control trips is a common problem when commercial pro-

jects are commissioned.

Once the antifreeze solution has been added to the ground

loop and all air has been purged from the system, the entire

ground loop can be pressurized to the appropriate value as per

the system design requirements. If possible, the ground loop

circulators should be tested prior to starting the heat pump to

ensure that the loop is functioning properly.

Open Loop Systems

The temperature of the well water for open loop installa-

tions should be a minimum of 42°F (6°C) for the W-series and

45°F (7°C) for the WH-series. Refer to the Model Specific

Information chapter for a complete table of temperature opera-

tion limits.

Discharge water from the heat pump should be disposed

of as per the system piping diagram and local codes. Most

commonly, a return well will be required.

Open loop systems will require an ON/OFF or modulating

water valve to shut off the water flow when heat pump is not

running.

Water Quality Guidelines

The well water should be tested to be sure it meets mini-

mum standards. Poor water quality can lead to rapid heat ex-

changer failure or frequent servicing.

The well should not produce any sand. Sand will physically

erode heat exchanger surfaces, and quickly clog return

(injection) wells. Solids or TDS should be less than 1 ppm (1

mg/L) if a return well is used.

To avoid scale formation on the inside of the heat pump’s

outdoor loop coil, total hardness should be less than 350 ppm /

350 mg/L. In practice, scaling is very rarely a problem at north-

ern groundwater temperatures of 50°F or less because scale

does not generally form at low well water temperatures (unlike,

for example, in a domestic hot water tank). In more southern

climates, the hardness guideline will be a more important con-

sideration. Should scale form, heat pump performance will

gradually deteriorate, and will require periodic flushing with a

calcium/lime removing solution (see Routine Maintenance).

Corrosive (salty) water is a concern, since although the

brazed plates are made of corrosion-resistant 316SS, the cop-

per brazing is susceptible to attack by chlorides. The water

should be tested and fall within the limits in the following table.

If it doesn’t, the use of an open loop system should be reconsid-

ered.

TABLE 12 - Water Quality Limits

Water Property Should be

Chlorides < 300 ppm

pH > 7.5

Ammonia (NH3) < 2 ppm

Hydrogen Sulfide (H2S) < 0.05 ppm

Sulfate (SO42-) < 70 ppm

Solids (TDS) < 1 ppm

Hardness < 350 ppm

Note that mg/L = ppm, and see notes above table.

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Nordic W/WH-Series Dual Circuit Owner's manual

Nordic W/WH-Series Dual Circuit Owner's manual

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